Conventionally, in a non-contact power transmitting system, there is known a configuration for carrying out radio communication between a power supplying appliance and a power receiving appliance to improve usability and reliability of the power supplying appliance and the power receiving appliance, (for example, refer to Patent Literature 1).
FIG. 31 is a block configuration diagram of a conventional non-contact power receiving appliance and a conventional non-contact power supplying appliance described in Patent Literature 1. As shown in FIG. 31, in a conventional technique, appliance body 420 corresponds to a non-contact power supplying appliance, and remote control device 401 corresponds to a non-contact power receiving appliance.
Remote control device 401 includes power-receiving resonance circuit 405a and communication resonance circuit 405b. Resonance circuit 405a is used to wirelessly receive power transmitted from appliance body 420, based on a change in a magnetic flux generated from appliance body 420, to input an instruction to appliance body 420 and output information concerning appliance body 420. Resonance circuit 405b is used to wirelessly carry out bidirectional communication of a communication signal with appliance body 420.
Appliance body 420 includes power-supplying resonance circuit 422 corresponding to resonance circuit 405a, communication resonance circuit 421 corresponding to resonance circuit 405b, and communication circuit 423.
FIG. 32, FIG. 33 are diagrams showing a concrete example of a non-contact power supplying appliance according to the conventional technique. The example shown in FIG. 32 is an inductive heating device in which two heating coils 426 are disposed spaced apart. The example shown in FIG. 33 is an inductive heating device in which many relatively small heating coils 426 are closely arranged in a matrix shape. FIG. 34 is a flowchart showing control for a non-contact power supplying appliance to detect remote control device 401 in the conventional technique.
FIG. 35 is a block configuration diagram of a conventional non-contact power receiving appliance and a conventional non-contact power supplying appliance described in Non-Patent Literature 1. Non-Patent Literature 1 prescribes specifications of a non-contact power transmitting system mainly for smartphones and mobile devices.
As shown in FIG. 35, the non-contact power transmitting system prescribed in Non-Patent Literature 1 includes base station 501 and mobile device 502.
From power conversion unit 506 of base station 501, power is contactlessly transmitted to power pick-up unit 507 of mobile device 502. Load 509 of mobile device 502 consumes the transmitted power.
During this period, base station 501 controls a magnitude of the transmitted power, in accordance with a magnitude of requested power transmitted from power receiver 505 of mobile device 502 to power transmitter 504 of base station 501 via communication control unit 508.
FIG. 36 is a state transition diagram of a conventional wireless charging system described in Non-Patent Literature 1. In selection state 601 shown in FIG. 36, the wireless charging system detects whether mobile device 502 is placed on base station 501.
For example, base station 501 detects placement of mobile device 502 by detecting a change in impedance. Upon detecting the placement of mobile device 502, base station 501 transits to ping state 602.
In ping state 602, base station 501 transmits micro power for operating communication control unit 508c, from power conversion unit 506 to power pick-up unit 507 of mobile device 502.
In this situation, when a response from mobile device 502 is not sent to base station 501 within a predetermined period via communication control unit 508, base station 501 returns to selection state 601. When the response is sent, base station 501 continues transmission of the micro power, and transits to identification state/setting state 603.
In identification state/setting state 603, mobile device 502 sends identification information and a magnitude of the requested power to base station 501 via communication control unit 508. When base station 501 determines it is adaptable to the magnitude of the requested power from mobile device 502, base station 501 completes the setting and transits to power supply state 604.
In power supply state 604, power transmission is carried out from power transmitter 504 of base station 501 to power receiver 505 of mobile device 502. The magnitude of transmitted power is controlled in accordance with the magnitude of the requested power transmitted from power receiver 505 of mobile device 502 to power transmitter 504 of base station 501. The transmitted power is consumed by load 509 of mobile device 502.
FIG. 37 shows a format of a communication packet used in the wireless charging system described in Non-Patent Literature 1. As shown in FIG. 37, the format of the communication packet includes preamble 701, header 702, message 703, and checksum 704.
Preamble 701 is data from 11 bytes to 25 bytes for detecting a communication packet. Header 702 is data of 1 byte to which a code corresponding to a type and a size of a message is allocated. Message 703 is data from 1 byte to 27 bytes corresponding to a code of header 702. Checksum 704 is data of 1 byte for detecting a packet error.
FIG. 38 is a diagram showing a relationship between a message size and a code of a header prescribed in Non-Patent Literature 1. FIG. 39 is a diagram showing a message type prescribed in Non-Patent Literature 1.
Non-Patent Literature 1 prescribes to use a message size from 1 byte to 27 bytes obtained by substituting a code within header 702 into an equation shown in FIG. 38. As shown in Non-Patent Literature 1 or FIG. 39, a packet type of a message and a message size corresponding to each code are prescribed. However, a detailed description will be omitted here.